Reliable laser welding of copper through short prepulsing

Reliable laser welding of copper
through short prepulsing
Concept
1) Frequency converted nanosecond laser pulse reliably sets starting conditions on copper surface
2) Laser welding with high power infrared laser
1), 2)
Key results
- Significant increase of process reliability (100% with 200 repetitions) and decrease of weld variation
- Power saving up to 40%
- Cost efficient and easy to integrate prepulse laser module
Pulse power
Without prepulsing
Prepulse
PP ~ 1MW
P ~ 5ns
With prepulsing
Welding pulse
PP ~ 1kW
P ~ 5ms
Pulse duration
Dummy spot welds on E-Cu58
Components and Systems
- Prepulse laser prototype, compact, rugged design, EP up to 2mJ, P =3-5ns, =526nm
- Optical systems for precise alignment of multiple wavelength laser spots
- Experimental welding setup with adjustable yet reliable beam manipulation
Prepulse laser prototype
Developed by neoLASE
Multi wavelength optical systems
Developed by Sill Optics
Experimental welding setup
Developed by LZH
1) Moalem, A., von Witzendorff, P., Frede, M., Kling, R.: Enhancing Process Stability in Infrared Laser Micro Welding of Copper using Frequency Converted
Short Prepulses, in proceedings of ICALEO 2010, Anaheim, USA
2) Frede, M. , Moalem, A.: Kleiner Laser, große Wirkung, Laser Technik Journal, 8: 20–23. doi: 10.1002/latj.201190002 (2011)
Applications
- Benefits demonstrated on micro welding of copper, platinum and gold parts
- New PCB design for laser welding
- Micro wires and IC leads
Platinum wire Ø 10μm
on contact pad (LTCC)
- first successful welding technology
for this application
LTCC developed by arteos
1 mm
Copper ribbon (150μm x 25μm)
on copper plated PCB
- PCB repair
- Alternative to ribbon bonding
Application by ILFA
IC (TSOP-05) on LASER-PCB
- tin free IC (stripped)
- PCB contact with locally increased depth
PCB developed by ILFA
Acknowlegements
- The project SUPREME was funded by the Federal Ministry of Education and Research (BMBF), and
- coached by the Project Management Agency Forschungszentrum Karlsruhe (PTKA).
arteos GmbH
die Kunste der Mikromontage
Dipl.-Ing. (FH)
Alexander Süllau
[email protected]
+49 511 95955-32
Dipl.-Ing. Winfried Korb
[email protected]
+49 6182 64034-0
Dipl.-Phys. Günter Toesko
Dr. rer. nat. Maik Frede
[email protected] [email protected]
+49 9129 902332
+49 511 2788-515
Booth C1.602
Booth C2.109
Dipl.-Ing. Anas Moalem
[email protected]
+49 511 2788-281
Booth C2.107